Field of the Invention
This invention relates to briquettes used in grills for cooking food over a bed of coals or the like and more particularly to briquettes containing aromatic pellets to provide volatile agents for flavoring food cooked over such briquettes.
Brief Description of the Prior Art
Although modern civilization has brought great convenience to the preparation and cooking of food, traditional methods of cooking have remained popular and have even been considered to be, in some respects at least, superior to newer techniques. This is particularly true in preparation of meat, where cooking over an open fire or a bed of coals has long been considered to give to the meat unique and desirable flavor, color and texture. Both in backyard "barbecue" cooking and in restaurants, meats prepared by grilling over open coals are often preferred for the color and flavor imparted by such cooking. Special woods have often been employed to give particular flavors to the meat. Thus, aromatic woods such as hickory, mesquite, apple, oak, maple, alder, cherry, sassafras, birch, ash, willow and some pines have been considered to provide characteristic flavors to the meat. Other aromatic materials such as spice hulls, nutshells, spices and mixtures thereof have also been added to the bed of coals or placed within the grill to impart flavor to the food as it is being cooked.
However, the use of wood for open cooking has a number of drawbacks. Relatively large amounts of wood have to be used to prepare a bed of coals suitable for grilling or cooking. Because seasoned firewood has a naturally high rate of burning, it burns, when first ignited, with abundant flames, which must be allowed to die down before a bed of coals suitable for cooking is available. This initial burning produces large volumes of smoke which can be unpleasant in confined locations such as a back yard or in the kitchen of a restaurant. Furthermore, it is the wood volatiles in the smoke that impart the characteristic color and flavor to the meat, and the wood fire does not release these volatiles in an efficient manner. In the initial stages of the fire, the flames are too intense for proper cooking, yet it is just at this time that the flavoring smoke is being evolved. Even if the cooking were attempted at this stage of the wood fire, the evolution of smoke and wood volatiles occurs at a rate too great for the meat to absorb them efficiently, and accordingly, a large fraction of the wood volatiles is wasted.
In order to overcome the problems inherent in cooking over a wood fire, it has long been customary to cook meats over a bed of coals prepared from charcoal. The charcoal burns with an essentially flameless fire that is easily controlled. Furthermore, the charcoal can be supplied in the form of briquettes molded from powdered charcoal that can be made from waste material such as sawdust. Such briquettes are uniform in size and properties and have come to be universally used for grilling meats over a charcoal fire. However, the pyrolysis of wood to make the charcoal removes most of the wood volatiles that are desired for flavoring meat. Consequently, meat prepared over a charcoal fire does not receive the special flavors imparted by the volatiles associated with a particular type of wood. Accordingly, even special charcoal such as that prepared from hickory wood cannot be the equivalent of the wood itself for imparting the characteristic hickory-smoked flavor to meats.
In order to obtain the advantageous properties of food cooked over open coals with the convenience of more modern sources of heat, non-combustible briquettes have been developed which are heated by a gas flame or electric resistance heating element in a gas or electric grill to simulate the hot coals of a charcoal fire and enable food to be cooked by the same desirable radiant heat. Such briquettes may be manufactured by simply crushing a durable rock such as basalt or "lava" to a suitable size or by molding from an inert filler such as clay or the like bonded with a heat-resistant binder such as portland cement. Certain briquettes have also been fabricated that combine both a combustible ingredient such as charcoal with a non-combustible ingredient such as clay to produce a briquette that can burn to provide heat by itself, yet remain intact after the combustible material has been used up to serve as a permanent briquette in gas or electrically heated grills. Such briquettes are disclosed in U.S. Pat. No. 4,787,914, to Crace.
However, combustible briquettes made from charcoal or noncombustible permanent briquettes used with gas or electric grills either do not supply wood volatiles or other volatile aromatic flavoring agents which are the agents that impart to the grilled meat its characteristic smoked flavor and color, or do not supply them in amounts sufficient for satisfactory flavoring.
A number of expedients have been tried in attempts to combine the flavoring properties of aromatic woods with the advantages of charcoal briquettes or permanent briquettes for open cooking of meats as well as to economize on the amount of wood needed.
Hinderer, U.S. Pat. No. 2,341,377, discloses a briquette comprising powdered charcoal and comminuted aromatic wood. The powdered material is mixed with a binder, molded into a briquette and hardened. However, this combination of powdered charcoal and comminuted wood has certain drawbacks. The individual particles of wood are subjected to the high temperatures of the charcoal flame as soon as it reaches them. Accordingly, the individual particles of wood tend to be rapidly combusted with accompanying destruction of the wood volatiles. Furthermore, the formulation of the briquette has to be specially adjusted to provide for binding of a briquette that comprises a substantial fraction of wood particles, and materials have to be added to prevent the wood particles from burning too rapidly. The physical integrity of the briquette as it burns is also affected by the rapid burning of the wood particles, and adjustments may have to be made to the binder, particularly if briquettes incorporating different proportions of comminuted wood are to be manufactured.
An alternative procedure, disclosed by Smith, U.S. Pat. No. 2,916,365, is to coat blocks of aromatic wood with flame retarding materials to control the rate of combustion. This procedure has the evident economic disadvantages of any method that starts with wood in any form to prepare a bed of coals and is wasteful of the aromatic wood. Furthermore, the preparation of wood blocks of appropriate size and shape from natural material is prohibitively expensive, as compared with preparation of charcoal briquettes from waste material such as sawdust.
U.S. Pat. No. 4,102,653, to Simmons et al., discloses an aromatic wood product for use in barbecuing foods which comprises wood impregnated or coated with combustion-retarding materials such as alkali metal salts, borax and the like to control the rate of release of wood volatiles for proper smoking of the food. The flame inhibition process may be applied to chunks, blocks or small logs of wood or to comminuted woods which are formed into briquettes. Simmons' products are intended to be used in association with conventional fuels such as nonaromatic wood, charcoal and gas. They are not capable of being used alone as a source of heat for cooking food on an open grill.
In all embodiments of Simmons' invention, the rate of emission of wood volatiles and the ultimate duration of the emission can only be determined by controlling the rate of combustion of the aromatic wood. The impregnation process itself introduces a complex step into the manufacture of the articles, whether it be used to impregnate blocks of wood to be used separately or comminuted wood to be incorporated into briquettes. Briquettes that are made entirely of comminuted wood and a binder have to be formulated or densified by compression so that the burning rate is controlled to release wood volatiles over the period of cooking. Furthermore, Simmons' coated or impregnated wood blocks suffer from the economic disadvantages of the coated blocks of Smith, U.S. Pat. No. 2,916,365, discussed above.
The Simmons patent does not disclose a combustible briquette that can alone provide both heat and wood volatiles, nor a permanent partially combustible or noncombustible briquette that can supply wood volatiles when heated by an extraneous source of heat, e.g., in a gas-fired or electric grill. While some embodiments of Simmons' briquettes are intended to have some structural integrity after combustion, they are not disclosed as being capable of functioning as permanent briquettes in gas grills and the like.
Crace, U.S. Pat. No. 5,096,727, discloses a composition containing aromatic woods and/or spices which is placed in a container between a bed of coals and the meat being cooked. The aromatic ingredients of the composition are vaporized by the heat of the coals and impart flavor to the meat. While this is an effective flavoring technique, it requires a separate composition and an additional piece of apparatus in the grill.
Accordingly, a need has continued to exist for an economical briquette, simple to manufacture, that can serve as a sole source of volatile aromatic agents for flavoring meat cooked over a bed of such briquettes.